How Many Generations Does DNA Go Back?

Popularity in finding out about our own DNA has risen over the past number of years, especially since we can buy tests to take in the privacy of our own homes, making it particularly convenient in our busy day-to-day lives.

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The rise of genealogy websites has also given many the interest of wanting to find out more about their past, and rightly so. It is fascinating to find out how you came to be on this earth and who lived before you in the family tree. 

How Many Generations Does DNA Go Back?

The most common type of DNA testing for genealogy that you’ll come across is an autosomal DNA test. Not only do they tell you your DNA matches, but also your ethnicity, an example being that you could be 40% English and 20% Irish, etc.

This is very useful because it can give you an insight into where your family roots have come from, and what ethnicity they were. But what about how far back the DNA tests can go? There are a number of factors that will determine this, so let’s take a look.

What Actually Is Autosomal And How Does It Work?

Autosomal, in simple terms, is a chromosome that can be tested to find segments of DNA a person may share with those they are both maternally and paternally, directly and indirectly, related to.

You could say it is an all-rounder, as it is suitable for all genders to take the test to find answers, rather than needing a specific chromosome. If you are after something more specific, then there are tests that are allocated towards those needs. These are explained further on.

This autosomal DNA test has been known to be very accurate. It is able to give you a general idea of your historic DNA. People tend to like this one because of the ethnicity percentage, which is handy if you want to know extra information.

Who doesn’t like to tell everyone that they are 10% Scottish and 40% Irish?  

How Far Will Autosomal Go Back?

It all depends on what company’s DNA testing kit you use which determines how far back a DNA test will go. Another factor is what type of test you use, as some can go as far back as your original origins, though there are restrictions on what you can find and who can take the test.

Something like 23andMe or AncestoryDNA, with an assumption of 25 years per generation, will go back to around 6 to 8 generations. So, about 150 to 200 years.

It is always worth doing your research when it comes to finding a company that does DNA testing, as some may not be suitable for what you are looking for as an end result. 

What Is A Y-DNA test?

If you are looking for something more specific, then a Y-DNA test or mtDNA test may be what you are after. The difference between these two tests compared to the autosomal is that they are gender specific, whether that is who is taking the test or what the outcome may be.

A Y-DNA test can trace back to your origins through the male-line (patrilineal), so a male with a Y-chromosome will need to do the test for this.

The patrilineal male-line – which is usually taken by a brother, father, or a paternal uncle and grandfather – can uncover a Y-chromosome haplogroup. This is an ancient group of people that descends from a person’s patrilineage. 

This can be an exciting route to take to find out about a particular direct paternal or maternal line of family that goes all the way back to your ancient origins. 

What Is An mtDNA Test?

An mtDNA test is similar to the Y-DNA test, except there are no exceptions on gender of the person taking the test. It only gathers results from the mother-line (matrilineal) via their mitochondria, which is passed from mothers onto their children.

Mitochondria, a cell found in our body, is something everyone has, hence anybody can take the test. Even so, because mitochondria are only passed on by females (mothers to children), only females will be in the results. 

Again, like with the Y-DNA test, it uncovers the mtDNA haplogroup. This group of ancient people descends from a person’s matrilineage.

Whilst both of these DNA tests are interesting, it is worth noting that the autosomal test may likely give you the results you want due to the nature of what it gathers – an overall result of your family history – but it may not go as further back as you would hope for.

Do The Y-DNA and mtDNA Go Further Back?

Yes, it can do, it just all depends on the results of the individual test. For example, the mtDNA test can show both recent and distant generations. The HVR (hypervariable region) number on a DNA test will determine a haplogroup – one’s genetic group of people that share a common ancestor on the patriline or matriline line.

So, there is a 50% possibility that if you match with someone on HVR1 that you share a mutual maternal ancestor going back around 1,300 years. The lower number suggests a low-resolution region.

If you match on both HVR1 and HVR2 (high-resolution region), then it means there is a 50% chance you share a related maternal ancestor spanning 28 generations – or around 700 years.   

Final Thoughts

The things to remember about finding your DNA history is to first plan what it is you are looking for, research what kits are available to you and your family, and what steps you need to take to gather the results. 

There can be a lot of results to take in at the end, but doing further research can help you determine what it all means. An autosomal DNA test is a great way to look at more recent DNA results and ethnicity, but a Y-DNA and mtDNA will span back even further generations, but can be limited.

You may actually find the results very surprising, so much so that it could take you on a long and enjoyable journey into your family’s history.